code: def testTFCompilableMetricsAccumulatorWithFirstEmptyInput(self):
      acc = tf_metric_accumulators.TFCompilableMetricsAccumulator(
          metric_counts=[1, 2, 3],
          padding_options=config_pb2.PaddingOptions(
              label_float_padding=-1.0,
              prediction_float_padding=-1.0,
          ),
      )
  
      self.assertEqual(0, acc.len_inputs())
  
      acc.add_input(0, None, None, None)
  
      acc.add_input(
          1,
          np.array([1.0, 1.0, 1.0]),
          np.array([0.3, 0.7]),
          np.array([1.0]),
      )
      acc.add_input(
          2, np.array([0.0, 0.0]), np.array([0.2, 0.8]), np.array([0.5])
      )
      self.assertAllClose(
          acc.get_inputs(1),
          (
              np.array([[1.0, 1.0, 1.0]]),
              np.array([[0.3, 0.7, -1.0]]),
              np.array([[1.0]]),
          ),
      )
      self.assertAllClose(
          acc.get_inputs(2),
          (
              np.array([[0.0, 0.0, -1.0]]),
              np.array([[0.2, 0.8, -1.0]]),
              np.array([[0.5]]),
          ),
      )
  
file_path: model-analysis/tensorflow_model_analysis/metrics/tf_metric_accumulators_test.py
imports: import numpy
  import tensorflow
  from tensorflow_model_analysis.eval_saved_model import testutil
  from tensorflow_model_analysis.metrics import tf_metric_accumulators
  from tensorflow_model_analysis.proto import config_pb2
label_desc: Use image node_id 3 for calling the TfMetricAccumulatorsTest obj's underlying member method code with example usage: obj.testTFCompilableMetricsAccumulatorWithFirstEmptyInput() without return types